如何获得该对象（如果存在）或“无”（如果不存在）？ [英] How do I get the object if it exists, or None if it does not exist?

问题描述

当我请求模型管理器获取对象时，如果没有匹配的对象，它将引发 DoesNotExist 。

When I ask the model manager to get an object, it raises DoesNotExist when there is no matching object.

go = Content.objects.get(name="baby")

代替 DoesNotExist ，如何让 go 成为 None

Instead of DoesNotExist, how can I have go be None instead?

推荐答案

没有内置方式来执行此操作。 Django每次都会引发DidNotExist异常。
在python中处理此问题的惯用方式是将其包装在try catch中：

There is no 'built in' way to do this. Django will raise the DoesNotExist exception every time. The idiomatic way to handle this in python is to wrap it in a try catch:

try:
    go = SomeModel.objects.get(foo='bar')
except SomeModel.DoesNotExist:
    go = None

我要做的是继承模型。Manager，像上面的代码一样创建 safe_get ，并在模型中使用该经理。这样，您可以编写： SomeModel.objects.safe_get（foo ='bar’）。

What I did do, is to subclass models.Manager, create a safe_get like the code above and use that manager for my models. That way you can write: SomeModel.objects.safe_get(foo='bar').

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